[mapserver-users] Draw roads WITHOUT anti-aliasing
Erik H
erik.h11.01 at gmail.com
Wed Oct 18 18:07:42 PDT 2017
Andreas,
I made that change in mapagg.cpp and it seems to do exactly what I need.
Wunderbar!
As for providing an option to switch rasterizer based on an option, how
about reviving the FORMATOPTION 'ANTIALIAS'?
Thanks, Erik
On Wed, Oct 18, 2017 at 9:18 AM, Eichner, Andreas - SID <
Andreas.Eichner at sid.sachsen.de> wrote:
> Nope, this won't work:
>
> r->default_gamma = atof(msGetOutputFormatOption( format, "GAMMA", "0.75"
> ));
> if(r->default_gamma <= 0.0 || r->default_gamma >= 1.0) {
> r->default_gamma = 0.75;
> }
>
> From mapagg.cpp lines 844-847 forces 0 < GAMMA < 1
> Also note that MapServer uses a linear gamma function defined as
>
> double operator() (double x) const
> {
> if(x < m_start) return 0.0;
> if(x > m_end) return 1.0;
> return (x - m_start) / (m_end - m_start);
> }
>
> Where m_start is _always_ set to 0 and m_end is set to the GAMMA value
> given by you (or the default 0.75).
> I think someone should check this - to me it seems a power function was
> intented...
>
> HTH
>
> > -----Ursprüngliche Nachricht-----
> > Von: mapserver-users [mailto:mapserver-users-bounces at lists.osgeo.org] Im
> > Auftrag von lars.schylberg at blixtmail.se
> > Gesendet: Mittwoch, 18. Oktober 2017 14:05
> > An: mapserver-users at lists.osgeo.org
> > Betreff: Re: [mapserver-users] Draw roads WITHOUT anti-aliasing
> >
> > Hi,
> >
> >
> >
> >
> > I did some quick tests with :
> >
> >
> >
> >
> > OUTPUTFORMAT
> > NAME "png_G0"
> > DRIVER AGG/PNG
> > MIMETYPE "image/png"
> > IMAGEMODE RGB
> > EXTENSION "png"
> > FORMATOPTION "GAMMA=0.0"
> > END
> >
> >
> >
> >
> > and shp2img with options -i
> >
> >
> > eg: shp2img -m 01_polygon_td_poly.map -o 01_polygon_td_poly.png -i
> > png_G0
> >
> >
> >
> >
> >
> > I did some tests with both polygons, polygon outlines and lines and they
> > all seems to have anti-aliasing as far as I could see.
> >
> > Would this be an ok way to test it? I also have some people that would
> > like to do lines without anti-aliasing for a strange reason.
> >
> >
> >
> >
> >
> > Lars Schylberg
> >
> >
> >
> >
> >
> > -----Originalmeddelande-----
> > > Från: "Rahkonen Jukka (MML)" <jukka.rahkonen at maanmittauslaitos.fi>
> > > Till: "Eichner, Andreas - SID" <Andreas.Eichner at sid.sachsen.de>, "Erik
> > H" <erik.h11.01 at gmail.com>
> > > Kopia: mapserver-users at lists.osgeo.org
> > > Datum: 2017-10-18 11:13
> > > Ämne: Re: [mapserver-users] Draw roads WITHOUT anti-aliasing
> > >
> > > Hi,
> > >
> > > I suppose that the amount of antialiasing with AGG is set with "gamma"
> > parameter. Mapserver supports that at least for polygons as documented
> > in http://www.mapserver.org/mapfile/outputformat.html but you could try
> > if using gamma=0.0 has an effect on lines as well. It may be that it
> > does not because search
> > >
> > https://github.com/mapserver/mapserver/search?utf8=%E2%9C%93&q=gamma&typ
> > e=
> > > seems to find only something that is tied to polygon outlines
> > > https://github.com/mapserver/mapserver/blob/branch-7-
> > 0/renderers/agg/include/agg_renderer_outline_aa.h
> > >
> > >
> > > If gamma does not work for lines then it could be worth making a
> > feature request for adding a new formatoption "GAMMA_LINE=[].
> > >
> > > Couple of Mapnik links dealing with the same issue:
> > > http://gis.19327.n8.nabble.com/Turning-off-anti-aliasing-
> > td5339458.html
> > > http://mapnik.org/mapnik-reference/#3.0.6/line-gamma-method
> > >
> > > -Jukka Rahkonen-
> > >
> > >
> > >
> > > -----Alkuperäinen viesti-----
> > > Lähettäjä: mapserver-users [mailto:mapserver-users-
> > bounces at lists.osgeo.org] Puolesta Eichner, Andreas - SID
> > > Lähetetty: 18. lokakuuta 2017 9:57
> > > Vastaanottaja: Erik H <erik.h11.01 at gmail.com>
> > > Kopio: mapserver-users at lists.osgeo.org
> > > Aihe: Re: [mapserver-users] Draw roads WITHOUT anti-aliasing
> > >
> > > Damn... missed attaching the images.
> > >
> > > > -----Ursprüngliche Nachricht-----
> > > > Von: mapserver-users [mailto:mapserver-users-
> > bounces at lists.osgeo.org]
> > > > Im Auftrag von Eichner, Andreas - SID
> > > > Gesendet: Mittwoch, 18. Oktober 2017 08:28
> > > > An: Erik H
> > > > Cc: mapserver-users at lists.osgeo.org
> > > > Betreff: Re: [mapserver-users] Draw roads WITHOUT anti-aliasing
> > > >
> > > > Hi,
> > > >
> > > > I just meant that it seems to be pretty easy to implement aliased
> > > > rendering with AGG.
> > > > Simply changing the typedef in line 91 of mapagg.cpp from
> > > >
> > > > typedef mapserver::renderer_scanline_aa_solid<renderer_base>
> > > > renderer_scanline;
> > > >
> > > > to
> > > >
> > > > typedef mapserver::renderer_scanline_bin_solid<renderer_base>
> > > > renderer_scanline;
> > > >
> > > > turns of anti-aliased rendering. I've attached the output of
> > "shp2img
> > > > -m line_simple.map" from the msautotests.
> > > > An additional member in class AGG2Renderer for the aliased
> > rasterizer
> > > > and conditionally passing one or the other to render_scanlines()
> > > > depending on some value of strokeStyleObj might be enough.
> > > >
> > > > Regards
> > > >
> > > > > -----Ursprüngliche Nachricht-----
> > > > > Von: Erik H [mailto:erik.h11.01 at gmail.com]
> > > > > Gesendet: Dienstag, 17. Oktober 2017 17:34
> > > > > An: Eichner, Andreas - SID
> > > > > Cc: Richard Greenwood; mapserver-users at lists.osgeo.org
> > > > > Betreff: Re: [mapserver-users] Draw roads WITHOUT anti-aliasing
> > > > >
> > > > > As for Andreas' remark about 'simply the use of another scanline
> > > > > rasterizer.' - I'm sorry but I'm not much of a C++ developer. If I
> > > > have
> > > > > to do rasterizing, I'd skip MapServer altogether and generate the
> > > > > PNG
> > > > in
> > > > > Java.
> > > > >
> > > > _______________________________________________
> > > > mapserver-users mailing list
> > > > mapserver-users at lists.osgeo.org
> > > > https://lists.osgeo.org/mailman/listinfo/mapserver-users
> > > _______________________________________________
> > > mapserver-users mailing list
> > > mapserver-users at lists.osgeo.org
> > > https://lists.osgeo.org/mailman/listinfo/mapserver-users
> >
> >
> >
> >
> >
> >
> >
> > --
> >
> >
> _______________________________________________
> mapserver-users mailing list
> mapserver-users at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/mapserver-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/mapserver-users/attachments/20171018/f3b590d7/attachment.html>
More information about the mapserver-users
mailing list